Last updated: April 2026
TLDR
Deutsche Telekom and Türk Telekom are running disaggregated broadband access networks in live production using VOLTHA, an open source project hosted by LF Broadband. A new working document, WT-525, is now formally mapping VOLTHA’s interfaces to the Broadband Forum’s CloudCO framework, creating the standardised foundation that makes AI-driven network automation viable at carrier scale.
Event Overview
LF Broadband and the Broadband Forum co-hosted this webinar on building intelligent broadband networks through the combination of open source software and carrier-grade standards. Four speakers from Vodafone, Deutsche Telekom, and Netsia walked through the evolution of disaggregated access architecture, the technical work underway to align open source with standards, and the concrete deployments already running in production.
Speakers:
- Bruno Cornelia, Vodafone
- Serkant Uluderya, Netsia
- Manuel Paul, Deutsche Telekom
- Bjoern Nagel, Deutsche Telekom
Hosted by: Dan Brown, Director of Communications, LF Broadband
Key Highlights
The Production Reality: VOLTHA Is Already in Carrier Networks
Bjoern Nagel opened the deployment discussion with a direct statement: VOLTHA is in live production today at Deutsche Telekom and Türk Telekom. These are tier-one operators running real subscriber traffic, not pilots, not proofs of concept.
Deutsche Telekom’s deployment is a brownfield modernisation at national scale. The programme, called Access 4.0, has achieved fully automated, zero-touch provisioning. Once fibre, cabling, and power are in place, every subsequent management, provisioning, and configuration process runs without human intervention.
Türk Telekom’s deployment follows a similar architecture, with a measurable reduction in both capital and operational expenditure and cloud-like agility in the access network. Additional operators have VOLTHA-based solutions in various stages of lab and field trials.
Both cases use VOLTHA alongside the SEBA (SDN-enabled broadband access) reference design architecture to deliver vendor-agnostic abstraction of OLT hardware, eliminating vendor-specific management silos and the repeated integration costs that come with them.
Read the full case studies: Deutsche Telekom Utilizes Open Source VOLTHA to Modernize Fixed-Access Network | Türk Telekom Transforms Access Network with Open Source VOLTHA
The Standards Layer: What WT-525 Does
Serkant Uluderya from Netsia presented WT-525 (Virtual OLT Hardware Abstraction Alignment with Cloud-CO), a working text document in the Broadband Forum that formally maps VOLTHA and the SEBA Reference Design 2.0 to the Broadband Forum’s CloudCO Issue 1.0 architectural framework.
The document addresses three layers of architecture:
- Northbound API (NBI): Maps the SEBA northbound interface to the CloudCO Occo-Nf-sdn-access interface — the point at which OSS systems communicate with the network.
- SDN Management and Control (SDN M&C): Maps individual software components, including the SEBA Network Edge Mediator (NEM), to the equivalent Access SDN M&C blocks in the CloudCO architecture, covering subscriber management and device control logic.
- Southbound API (SBI): The most technically complex layer. VOLTHA uses the OpenOLT gRPC API, while Broadband Forum specifications standardise NETCONF (Minf and Mfc interfaces) toward the physical OLT. Both share YANG for data modelling, which provides the common data model that allows a disaggregated OLT to present as a set of standard logical blocks to the orchestration layer, regardless of the underlying vendor hardware.
WT-525 is a concrete technical specification that identifies where interfaces align, where gaps exist, and what is required to achieve full interoperability.
Why Standards Alignment Is the Prerequisite for AI
Serkant framed the connection between WT-525 and AI plainly: if data varies from one OLT to the next, AI models will be unreliable, regardless of algorithm sophistication. Multi-vendor environments historically produce inconsistent telemetry, with different vendors reporting the same metric in different formats. Building network-wide AI intelligence on that foundation is not viable.
WT-525 addresses this at the foundation by mandating common YANG data models across the stack and routing telemetry through standardised BBF interfaces. The result is a single, unified data stream across the deployment, regardless of the hardware underneath.
With consistent data in place, three capabilities become practical:
- Closed loop automation: AI can detect service degradation, send standardised instructions to the SDN control layer, and receive telemetry confirmation that the fix has worked, without human intervention.
- Intent-based networking: Operators specify outcomes, and the AI layer translates those into standardised MBI calls executed hardware-agnostically by the SDN layer.
- Stable northbound interfaces: Because the northbound interface is standardised through WT-525 alignment, business-level policies remain valid even when underlying hardware or VOLTHA versions change.
The Path to Autonomous Network Operations
Manuel Paul from Deutsche Telekom outlined the strategic direction for LF Broadband and its partnership with the Broadband Forum. Key areas of focus include:
- Network optimisation and intelligence: Predictive maintenance, closed loop fault remediation, and dynamic experience management that responds to network conditions in real time.
- Infrastructure efficiency: Fibre planning, split optimisation, and energy-aware access network operation — matching network behaviour to actual traffic demand rather than running at constant capacity.
- Home and edge intelligence: Edge inference via service edges and next-generation gateways, with significant opportunity in CPE-level service quality given the scale of deployment.
Manuel was clear that the move from AI-assisted operations to near-autonomous, policy-driven operation will take time and will require operators to build confidence in the system. VOLTHA’s deterministic APIs, auditability, and operator visibility are positioned as the foundation for that confidence — the same properties that drove SDN adoption are expected to enable the same learning curve with AI.
The CloudCO Architecture Foundation
Bruno Cornelia from Vodafone provided context on the Broadband Forum’s CloudCO framework, designed to create an interoperable environment across the disaggregated access stack. The framework defines clear boundaries and interfaces at every layer, from virtualised functions and controllers through to domain orchestrators and end-to-end network orchestrators, so that operators can select different vendors for different components without creating integration dependencies.
The disaggregated OLT model, defined in TR-477, and the disaggregated BNG model, defined in TR-459, specify which functions are separated and how they communicate. WT-525 now formally connects this architecture to the VOLTHA open source implementation.
Recordings and Resources
- VOLTHA 2.15 release notes and full changelog: lfbroadband.org/projects/voltha
- WT-525 deep dive: Bridging LF Broadband Open Source with Broadband Forum Standards
- Deutsche Telekom case study: lfbroadband.org
- Türk Telekom case study: lfbroadband.org
What Is Next
LF Broadband is actively building the community that will define the next phase of intelligent broadband infrastructure. Operators, vendors, and researchers can contribute requirements, influence the open source stack, and shape the standards alignment work through both LF Broadband and the Broadband Forum.
VOLTHA 2.15, released in February 2026, introduced PLOAM-level ONU disable/enable support for improved fault isolation, enhanced PM statistics including XGSPON-ready counters and a new upstream HEC error metric, OLT IP address update without reprovisioning, and gRPC statistics enabled across VOLTHA modules.
To get involved in the VOLTHA community: Contact the VOLTHA Technical Steering Team at lists.voltha.org/g/Discuss
To learn more or become a member: lfbroadband.org/join
Frequently Asked Questions
What is VOLTHA and where is it deployed? VOLTHA (Virtual OLT Hardware Abstraction) is an open source project for disaggregated broadband access, hosted by LF Broadband. It is currently in live production at Deutsche Telekom and Türk Telekom, with additional operators running VOLTHA-based solutions in lab and field trials.
What problem does WT-525 solve? WT-525 is a Broadband Forum working text that formally maps VOLTHA and the SEBA Reference Design 2.0 to the CloudCO framework. It resolves the interoperability gap between open source development and carrier-grade standards, and creates the standardised data foundation required for reliable AI-driven network automation.
Why is consistent telemetry critical for AI in broadband networks? AI models are highly sensitive to inconsistent inputs. In a multi-vendor environment where different OLTs report the same metrics differently, models cannot generalise reliably across the network. WT-525 mandates common YANG data models and standardised telemetry interfaces to produce a unified data stream regardless of hardware vendor.
How does VOLTHA support the move to autonomous network operations? VOLTHA’s deterministic APIs, auditability, and operator control provide the confidence layer that operators need before reducing human intervention. The architecture supports closed loop automation — where AI detects, acts, and confirms without manual steps — as well as intent-based networking where operators define outcomes rather than configurations.
How can my organisation get involved? Both LF Broadband and the Broadband Forum are open to new members and contributors. Participants can bring operator requirements into the open source stack, contribute to WT-525 development, and influence the direction of the AI-ready access network roadmap. Visit lfbroadband.org/join to learn more.
About LF Broadband
The LF Broadband Directed Fund was established in late 2023 as an independent fund under the Linux Foundation. LF Broadband supports a collection of projects that transformed broadband networks and the Passive Optical Network (PON) industry, including the SEBA reference design for building open broadband networks, and the VOLTHA open source project for virtualising multi-vendor PON systems. Learn more at lfbroadband.org.
About The Linux Foundation
The Linux Foundation is the world’s leading home for collaboration on open source software, hardware, standards, and data. Linux Foundation projects are critical to the world’s infrastructure including Linux, Kubernetes, Node.js, ONAP, OpenChain, OpenSSF, OpenStack, PyTorch, RISC-V, SPDX, Zephyr, and more. The Linux Foundation focuses on leveraging best practices and addressing the needs of contributors, users, and solution providers to create sustainable models for open collaboration. For more information, please visit linuxfoundation.org.
Last updated: April 2026
